1. Field of the Invention
The present invention relates to an image reading device and a printing apparatus that include a transport unit for transporting a medium by using negative pressure.
2. Description of the Related Art
Transport using a belt and transport using a drum are known as a method of transporting a medium in an image reading device. In the transport using a belt, a medium is transported in a sub-scanning direction while being sucked on the peripheral surface of an endless belt going around (for example, JP2003-209663A and the like). In the transport using a drum, a medium is transported in a sub-scanning direction while being sucked on the peripheral surface of a rotating drum (for example, JP2005-126215A and the like).
In both the transport using a belt and the transport using a drum, negative pressure is used for the suction of the medium. In the case of the transport using a belt, a plurality of suction holes are formed on the peripheral surface of the belt and a medium is sucked on the peripheral surface of the belt by the suction of air from the inside of the belt. In the case of the transport using a drum, a plurality of suction holes are formed on the peripheral surface of the drum and a medium is sucked on the peripheral surface of the drum by the suction of air from the inside of the drum.